Effects of electrical stimulation and tetrodotoxin paralysis on antigenic properties of acetylcholine receptors in rat skeletal muscle.
To examine the role of muscle activity in the expression of fetal- and adult-type acetylcholine receptors (AChRs), we studied the effects of muscle stimulation in cell culture and of tetrodotoxin (TTX)-induced paralysis and denervation in adult rat muscles. The AChR content of these muscles was determined using [125I]alpha-bungarotoxin and the proportion of fetal-type receptors was estimated using a radioimmunoprecipitation assay with a myasthenic serum that was highly specific for fetal-type receptors. We found that both stimulated, aneural muscle cells in vitro and inactive muscles in vivo produced predominantly fetal-type AChRs. However the TTX-paralysed muscles had a lower proportion of fetal-type receptors than the denervated muscles. We conclude that neither muscle activity nor innervation alone, but a combination of both, is required for full regulation of AChR antigenicity.
O'Malley
J P
JP
Department of Physiology, University of Otago Medical School, Dunedin, New Zealand.
Mills
R G
RG
Bray
J J
JJ
D000818:Animals; D002038:Bungarotoxins / Q000378:metabolism; D002478:Cells, Cultured; D004558:Electric Stimulation; D004622:Embryo, Mammalian; D009121:Muscle Denervation; D009132:Muscles / Q000187:drug effects / Q000502:physiology* / Q000503:physiopathology; D010243:Paralysis / Q000139:chemically induced / Q000503:physiopathology*; D011863:Radioimmunoassay; D051381:Rats; D011950:Receptors, Cholinergic / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D013779:Tetrodotoxin / Q000633:toxicity*
D002038:Bungarotoxins; D011950:Receptors, Cholinergic; D013779:Tetrodotoxin